By 2005, the pharmaceutical industry will spend $7.5 billion annually on direct-to-consumer advertising (DTCA) of prescription drugs. Proponents of DTCA say it encourages productive discussions between patients and physicians, while critics charge that it increases unnecessary prescribing, raises costs, and strains the patient-clinician relationship. Empirical evidence for policymaking in this area is lacking. This study will examine the clinical impact of DTCA by conducting an experiment using standardized patients (SPs) who present with depressive symptoms (representing either major depression or adjustment disorder) and make either: 1) an ad-driven request for a brand-name antidepressant, 2) a generic request for treatment, or 3) no request. Our focus on depression is justified by the high prevalence and costs of this condition, its relevance to general medical practice, the ubiquity of depression-related DTC ads in both broadcast and print media, and the broadening indications for the use of antidepressant medications. The application has 3 specific aims: 1) to estimate the effects of DTC ad-driven requests on physicians' prescribing of antidepressants for patients with depressive symptoms; 2) to determine whether DTC ad-driven requests are associated with better or worse quality of care in primary care settings; and 3) to describe differences in physicians' communication behaviors when they are confronted by patients making ad-driven requests, generic requests, and no specific requests. In this randomized trial, 144 primary care physicians in 3 U.S. cities will each see 2 unannounced SPs. The SPs will be trained to portray 6 different roles, generated by crossing 2 clinical presentations (major depression and adjustment disorder) with 3 request conditions (DTCA activated, generically activated, and no request). Visits will be audio-recorded, and SPs will record physicians' clinical behaviors. Using multi-level mixed effects models, data will be analyzed to assess the influence of DTCA on antidepressant prescribing and the clinical process of care. These analyses will be supplemented by qualitative and quantitative analyses of physician communication behaviors across experimental conditions. The results will address a pressing policy question (i.e., should DTCA be further regulated?) while also contributing to our understanding of the social influences on diagnosis and treatment of depression in primary care settings.